Note: USNO-A2.0 contains 526,280,881 sources, and is based on a re-reduction of the Precision Measuring Machine (PMM) scans from POSS-I O and E plates (>=-18°) and SRC-J and ESO-R plates (<=-20°). USNO-A2.0 was created by Dave Monet () and collaborators at Flagstaff Station, U.S. Naval Observatory.
The major difference between USNO-A2.0 and its previous version USNO-A1.0 is that A1.0 used the Guide Star Catalog as its reference frame whereas A2.0 uses the ICRF as realized by the USNO ACT catalog (Urban et al. 1997). The VizieR search engine uses an on-line compressed version (3.6Gbytes) which was generated at CDS.

Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	USNO-A2.0	RAJ2000 deg	DEJ2000 deg	ACTflag	Mflag	Bmag mag	Rmag mag	Epoch yr
1	2.523	06 15 55.43280	-55 56 51.2916	0300-02126657	093.980970	-55.947581			12.3	14.1	1981.462
2	12.537	06 15 57.09288	-55 56 46.3128	0300-02126910	093.987887	-55.946198			20.6	18.0	1981.462
3	23.787	06 15 53.42952	-55 57 04.3128	0300-02126362	093.972623	-55.951198			18.1	16.5	1981.462

%0a%0a%3cP%3e%0a%3cFONT%20SIZE=%27-1%27%3e%3cEM%3e%3cFONT%20COLOR=%27#0000FF%27>%3cB%3eNote:%20The%20%3cB%3eGuide%20Star%20Catalog%20has%20been%20constructed%20to%20support%20the%20%0aoperational%20need%20of%20the%20Hubble%20Space%20Telescope.%0aIt%20contains%20over%2025%20million%20positions%20for%20about%2019%20million%0aobjects,%20of%20which%20more%20than%2015%20million%20are%20classified%20as%20stars.%0aThe%20version%20%3cB%3e1.2%20is%20a%20new%20astrometric%20reduction%20which%20results%20in%0aabsolute%20position%20errors%20about%200.3-0.4%20arcsec.%0a%28see%20GSC%20pages%20at%20URL%20http://www-gsss.stsci.edu/gsc/gsc.html%29%0a%3cP%3e%0a

Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	GSC	RAJ2000 deg	DEJ2000 deg	PosErr arcsec	Pmag mag	e_ mag	n_	Class	Plate	Epoch yr
1	1.95	06 15 55.4904	-55 56 50.964	0853800401	093.98121	-55.94749	0.4	15.43	0.40	0	0	011E	1979.884
2	2.38	06 15 55.4328	-55 56 51.072	0853800401	093.98097	-55.94752	0.3	15.52	0.40	0	0	039N	1978.023

%0a%0a%3cP%3e%0a%3cFONT%20SIZE=%27-1%27%3e%3cEM%3e%3cFONT%20COLOR=%27#0000FF%27>%3cB%3eNote:%20The%20%3cB%3eGSC-ACT%20%3cEM%3e%28or%20%3cB%3eGSC1.3%29%0ais%20a%20recalibration%20of%20the%20%3cB%3e<%25E%20I/220%7cGSC1.1>,%20the%20catalogue%20constructed%20%0ato%20support%20the%20operational%20need%20of%20the%20Hubble%20Space%20Telescope,%0awith%20the%20%3cB%3e<%25E%20I/246%7cACT>,%20the%20combination%20of%20the%20Astrographic%20Catalogue%0aand%20the%20%3cB%3e%3cEM%3eTycho%20catalogue%20derived%20from%20the%20%3cEM%3e<%25E%20I/239%7cHipparcos>%0amission;%20see%20http://www.projectpluto.com/gsc_act.htm%20for%20more%20details%0aabout%20this%20recalibration.%0a%3cP%3e%0a%22>

>	\BegDIVclass='sort-down ' </A>
dec Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	GSC	RAJ2000 deg	DEJ2000 deg	PosErr arcsec	Pmag mag	e_ mag	n_	Class	Epoch yr
1	1.96	06 15 55.5072	-55 56 51.108	0853800401	093.98128	-55.94753	0.4	15.45	0.42	0	0	1979.884
2	2.28	06 15 55.4448	-55 56 51.036	0853800401	093.98102	-55.94751	0.3	15.54	0.41	0	0	1978.023

Note: The construction of the GSC-II is still in progress: this version has no proper motions, and the magnitude limits are 18.5 in F (red) and 19.5 in J (blue). The data are copyrighted, check the data use Policy.

Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	GSC2.2	RA(ICRS) deg	DE(ICRS) deg	Epoch yr	Rmag mag	e_ mag	Bjmag mag	e_ mag	Class	a pix	e
1	2.292	06 15 55.43856	-55 56 50.9964	S1123202167	093.980994	-55.947499	1993.888	15.14	0.43	13.81	0.31	3	7.31	0.07
2	23.277	06 15 53.44584	-55 57 03.6576	S11232028787	093.972691	-55.951016	1993.888	16.65	0.44	18.70	0.31	0	3.46	0.11

%0a%0a%3cP%3e%0a%3cFONT%20SIZE=%27-1%27%3e%3cEM%3e%3cFONT%20COLOR=%27#0000FF%27>%3cB%3eNote:%20The%20%3cB%3eUSNO-B%20Catalog%20presents%20positions,%20proper%20motions,%20%0amagnitudes%20un%20blue,%20red%20and%20infrared,%20as%20well%20as%20star/galaxy%20estimators%0afor%201,045,175,762%20objects%20derived%20from%203,648,832,040%20separate%20observations.%0aThe%20data%20were%20taken%20from%20scans%20of%207,435%20Schmidt%20plates%0ataken%20from%20various%20sky%20surveys%20during%20the%20last%2050%20years.%3cBR%3e%0aUSNO-B1.0%20catalog%20was%20created%20by%20Dave%20Monet%20and%20collaborators%0aat%20http://www.nofs.navy.mil/data/fchpix/%20%3cBR%3e%0a%3cB%3e%3cFONT%20COLOR=%27#EE0000%27>%20Note%20that%20the%20star/galaxy%20estimators%20may%20be%20mixed%20up%0a%20in%20dense%20regions.%0a%3cP%3e%0a

Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	USNO-B1.0	RAJ2000 deg	DEJ2000 deg	e_RAJ2000 mas	e_DEJ2000 mas	Epoch yr	pmRA mas/yr	pmDE mas/yr	Ndet	B1mag mag	R1mag mag	B2mag mag	R2mag mag	Imag mag
1	2.372	06 15 55.44288	-55 56 51.1620	0340-0053359	093.981012	-55.947545	40	153	1988.4	0	0	4		14.50	13.23	14.17	16.27
[****ClosingBrace(s)Inserted****]
">

%3cEM%3e1&%3cFONT%20COLOR=%27#CD5B45%27>%202.372&%3cFONT%20COLOR=%27#CD5B45%27>06%2015%2055.44288&%3cFONT%20COLOR=%27#CD5B45%27>-55%2056%2051.1620&0340-0053359&093.981012&-55.947545&%2040&153&1988.4&%20%20%20%20%200&%20%20%20%20%200&4&%20&14.50&13.23&14.17&16.27%3cBR%3e">\Ahref='VizieR-5?-ref=VIZ663ae415484af&-out.add=.&-source=I/284/out&USNO-B1.0===0340-0053360&-out.orig=o' class='full'2 3.71906 15 55.61736-55 56 45.85200340-0053360093.981739-55.9460709999991990.4 0 02  20.69    18.22 3 9.35806 15 54.82008-55 56 55.79160340-0053355093.978417-55.9488317339991987.9 0 04  19.9818.7218.9918.91 412.77606 15 57.11880-55 56 46.20120340-0053363093.987995-55.9461671991081988.2 0 04  19.2821.4919.3618.82 514.35806 15 57.25008-55 56 44.48040340-0053364093.988542-55.9456899999991986.6 542 7923  20.6720.4919.08   623.07806 15 53.47800-55 57 03.68280340-0053352093.972825-55.951023 43 971988.2 20 264  16.6318.7016.5815.34 %0a%0a%3cP%3e%0a%3cFONT%20SIZE=%27-1%27%3e%3cEM%3e%3cFONT%20COLOR=%27#0000FF%27>%3cB%3eNote:%20The%20Naval%20Observatory%20Merged%20Astrometric%20Dataset%20%28NOMAD%29%20contains%0aastrometric%20and%20photometric%20data%20for%20over%201%20billion%20stars%20derived%20from%0athe%20Hipparcos%20%28I/239%29,%20Tycho-2%20%28I/259%29,%20UCAC2%20%28I/289%29,%20and%20USNO-B1.0%0a%28I/284%29%20catalogs%20for%20astrometry%20and%20optical%20photometry,%20supplemented%0aby%202MASS%20%28II/246%29%20near-infrared%20photometry.%3cBR%3e%0a%3cFONT%20SIZE=%27-1%27%3eAn%20efficient%20remote%20query%20program%20%3cB%3efindnomad1%20is%0aavailable%20in%20the%20cdsclient%20%0apackage,%20for%20Unix/Linux%20platforms%0a%3cP%3e%0a

Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	NOMAD1	YM	RAJ2000 deg	DEJ2000 deg	r	pmRA mas/yr	e_ (...)	pmDE mas/yr	e_ (...)	Bmag mag	r_	Vmag mag	r_	Rmag mag	r_	Jmag mag	Hmag mag	Kmag mag	R
1	2.372	06 15 55.442664	-55 56 51.15984	0340-0053527	..	093.9810111	-55.9475444	B	0.0	0.0	0.0	0.0	13.230	B			14.170	B
2	3.721	06 15 55.617336	-55 56 45.84984	0340-0053528	..	093.9817389	-55.9460694	B	0.0	0.0	0.0	0.0					20.690	e
3	9.357	06 15 54.820008	-55 56 55.79016	0340-0053523	..	093.9784167	-55.9488306	B	0.0	0.0	0.0	0.0	18.720	B			18.990	B
4	12.776	06 15 57.118656	-55 56 46.20012	0340-0053531	..	093.9879944	-55.9461667	B	0.0	0.0	0.0	0.0	21.490	B			19.360	B
5	14.358	06 15 57.250008	-55 56 44.48004	0340-0053532	..	093.9885417	-55.9456889	B	542.0	298.0	792.0	131.2	20.490	B			19.080	B
6	23.077	06 15 53.478000	-55 57 03.67992	0340-0053520	YM	093.9728250	-55.9510222	B	20.0	3.0	26.0	7.0	17.530	Y			16.580	B	14.026	13.367	13.198
[****ClosingBrace(s)Inserted****]
6	23.077	06 15 53.478000	-55 57 03.67992	0340-0053520	YM	093.9728250	-55.9510222	B	20.0	3.0	26.0	7.0	17.530	Y			16.580	B	14.026	13.367	13.198

%22>\EndTABLESORT

Note: This version of the GSC-II has no proper motions, but the limits on brightness which existed on GSC2.2 (F<18.5, B_j<19.5) were removed.

Full	_r arcsec	_RAJ2000 "h:m:s"	_DEJ2000 "d:m:s"	GSC2.3	RAJ2000 deg	DEJ2000 deg	Epoch yr	Fmag mag	jmag mag	Vmag mag	Nmag mag	Class	a pix	e
1	2.290	06 15 55.43856	-55 56 50.9928	S4IQ000167	093.980994	-55.947498	1993.888	15.14	13.81		16.48	0	7.31	0.07
2	12.626	06 15 57.07920	-55 56 45.6180	S4IQ008851	093.987830	-55.946005	1993.888	19.22	22.23		18.77	3	2.84	0.26
3	23.274	06 15 53.44608	-55 57 03.6540	S4IQ008787	093.972692	-55.951015	1993.888	16.65	18.70		15.28	0	3.46	0.11
4	29.034	06 15 57.91800	-55 57 11.4804	S4IQ008737	093.991325	-55.953189	1993.888	20.46				3	1.61	0.38

%0a%0a